Typically in drug and vaccine development, first-to-market products command a big advantage that can deter follow-up products. Not so with COVID-19 vaccines, experts said Tuesday. There’s still plenty of need for new entrants.
Even as the first COVID-19 vaccines from Pfizer-BioNTech, Moderna and AstraZeneca are deploying in the U.S. and other countries, more programs will need to succeed to vaccinate the entire world, Swati Gupta, Ph.D., vice president and head of emerging infectious diseases and scientific strategy at IAVI, said on a Fierce JPM Week panel. IAVI, a nonprofit research group, is partnered with Merck & Co. on an early-stage candidate based on the same technology used in Merck's Ebola vaccine.
The ongoing COVID-19 vaccine launches will hopefully “help us to end the acute phase of the pandemic,” Gupta said, but, because COVID-19 is likely to become endemic, “we also need to plan for longer-term management of the disease.”
How many vaccines will be needed? Given the more than 8 billion people on the planet, Gupta sees the need for 16 billion vaccine doses under a two-dose regimen. The world will “definitely need” more vaccines to defeat the pandemic, she said. Plus, it isn't known how long protection will last from various vaccines.
Aside from the sheer demand, follow-up vaccines could offer advantages over the first programs. Follow-up vaccines could come in a single dose. They might be easier to scale up for mass manufacturing. They could be more stable at refrigerated temperatures, she said.
The first mRNA vaccines from Pfizer-BioNTech and Moderna posted efficacy figures above 90%, but Thomas Lingelbach, CEO of vaccine maker Valneva, said the industry and regulators should “agree that everything above 70% or 80% is a good efficacy for a vaccine.”
Head-to-head comparisons between vaccines are “not really relevant,” Lingelbach said. As programs from Valneva and numerous other biotechs move ahead, Lingelbach said he’s “absolutely sure” there will be demand for follow-up vaccines. Valneva's inactivated coronavirus vaccine candidate, VLA2001, is in a phase 1/2 trial.
Overall, the high level of efficacy seen for Pfizer and Moderna’s vaccines “doesn’t change much” for the companies pursuing their own programs, Nathalie Landry, executive vice president of scientific and medical affairs at Medicago, said during the discussion. Medicago and its partner GlaxoSmithKline recently entered a phase 2/3 trial for a plant-derived candidate.
"The rule is still to demonstrate significant efficacy, good immune response and monitor that efficacy for a long period of time,” she said.
Still, the process of testing a vaccine candidate poses challenges when there's already an authorized program. There will be a “moment in time” when a placebo-controlled trial isn’t feasible, Lingelbach said, either for “ethical reasons” or “practical reasons.” Right now, it’s “very difficult” to say when that moment will be.
When vaccines become widely available, many people would argue it’s not ethical to test against placebo because there’s “already something out there that works," Gupta said.
Researchers could run a noninferiority trial, Lingelbach and Gupta said, which would test whether the candidate works as well as existing vaccines. At the end of the day, regulators and researchers are going to need to work together to find the best approach given the circumstances, Gupta said.
Aside from the Pfizer, Moderna and AstraZeneca programs, which have scored authorizations in various countries, Novavax and Johnson & Johnson are in phase 3 testing for their shots. Dozens of other programs are in various stages of testing.
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